We completed this build for Scott. O, and we're sad to say it has to leave the shop today to go home to its new master! This custom carbine Pitbull was a super fun project, just one of many we hope to complete in the coming new year.
As you can see from the photos, this compact rifle fits nicely between the seat and center console of Matt's truck. Scott wanted his Pitbull to shoot .35 cal JSBs in the mid 900's, so we took it to the range for fine tuning, chrony testing and hammer spring adjustment. The sweet spot for fill pressure was discovered to be 2700-2750 PSI, which gave us a great balance of efficiency, power and accuracy. The rifle used about 100 PSI per shot. Matt shot a sub 1" group (0.721) with those big 'ole JSB diabolo slugs at 50 yards
We're also sending Scott our prototype cylindrical moderator dubbed the "Pug" for testing. In a quick and dirty decibel test, the un-moderated rifle got a reading of 128 dB, and with our Pug moderator it it looks like that number shrank to 103 dB.
Scott's carbine also received our full tune up and power mod, and we hope he enjoys his new rifle for years to come. We like this rifle so much, more than likely we'll have to make one for ourselves to play with here at the shop!
Thanks for the excellent work!
How about a video on how to make a puppy
Iamscotticus, I suspected that the JSAR valve would pass too much air for the lighter weight pellet. Still, the build is a winner all around. Looks great and does what it was built to do. I've seen quite a few that never quite meet the goals.
David, I wanted to give the JSAR a try but it didn't work out and we went with the OEM valve, which is adequate and allows a range of tuning. The diabolo pellets are not known to be high velocity performers, so some dialing back was necessary. The balanced valve is designed for the higher volumes so It didn't work right in my application. I suspect the shorter barrel cut the dwell time too much. I could be wrong.
I've gotta ask, is this the customer rifle that came in with a JSAR valve? I'm asking because a friend bought me one and I'm preparing to install it. And it's thanks to Matt that I feel confident enough to do the work myself. Okay, a friend with a machine shop will help me drill out the TP to ensure I don't make any avoidable mistakes by looking over my shoulder. But it has a lot to do with Matt's videos without which I would never have had the confidence to disassemble the Bulldog in the first place.